Articulated tracked vehicle

ABSTRACT

An articulated tracked vehicle comprising a first vehicle unit and a second vehicle unit controllably connected by means of a control member, wherein each vehicle unit comprises two tracks driven by drive wheels, wherein the first vehicle unit comprises a mechanical propulsion unit with a combustion engine for driving the drive wheels of the first vehicle unit and the second vehicle unit consists of one electric propulsion unit for driving the drive wheels of the second vehicle unit, wherein the combustion engine is arranged to drive a generator for electric power generation, wherein the generator is arranged to transfer electric power via power electronics to the electric propulsion unit of the second vehicle unit, wherein power transfer between said vehicle units is arranged to be effected only electrically.

RELATED APPLICATION DATA

This application is a continuation of U.S. patent application Ser. No.13/382,653 filed Mar. 19, 2012, which was a national phase ofInternational Application No. PCT/SE10/050782 filed Jul. 6, 2010, whichclaimed priority of Swedish Application No. 0950530-6 filed Jul. 7,2009, all of which are hereby incorporated herein by reference.

TECHNICAL FIELD

The invention relates to an articulated tracked vehicle.

BACKGROUND ART

Articulated tracked vehicles comprising a front vehicle unit and a rearvehicle unit controllably interconnected by means of a control coupling,wherein the vehicle comprises a driveline for driving the vehicle areknown. The driveline comprises according to prior art a diesel engine, agearbox connected to the diesel engine, distribution gear, and shaftgears for front and rear vehicle units, the shaft gears being arrangedto distribute the power to the respective track of the vehicle. Such adriveline occupies relatively large space and is relatively heavy.

U.S. Pat. No. 6,880,651 B2 discloses an articulated tracked vehicle witha driveline system having a first driveline comprising a diesel enginearranged in the front vehicle unit and a second driveline comprising anelectric motor/generator arranged in the rear vehicle unit. In the firstdriveline the diesel engine is arranged to drive a gear box which inturn is connected to a drop box arranged to drive a drive shaft beingconnected to the front shaft gear and rear shaft gear distributing thepower to the respective track. In the second driveline the drive shaftis connected to the electric motor/generator, wherein the electric motoris arranged to be driven by means of energy from a battery pack or acapacitor such that the tracks may be driven by means of the electricmotor. The first and second vehicle units may be disengaged wherein therespective vehicle unit may be driven by itself. Further the dieselengine and/or the electric motor may drive both vehicle units when thevehicle units are interconnected. A disadvantage with such aconstruction is that it occupies a lot of space due to among othersdouble drivelines and is also relatively heavy. Further batteries or acorresponding energy source are required in order to energize theelectric motor, which also occupies space.

SUMMARY OF THE INVENTION

The present invention provides an articulated tracked vehicle with adriveline which facilitates compact building-in in the vehicle such thatspace in the vehicle may be used more efficiently, and facilitatesimproved efficiency of the vehicle.

According to an embodiment the objects are achieved with an articulatedtracked vehicle comprising a first vehicle unit and a second vehicleunit controllably connected by means of a control member, wherein thefirst vehicle unit comprises a combustion engine, wherein the combustionengine is arranged to drive a generator for electrical generation,wherein the generator is arranged to transfer power via power electronicmeans to at least one electric motor of at least one electric propulsionunit.

Hereby no mechanical transmission of power is required from thecombustion engine to drive wheels of the vehicle, wherein relativelyoptional placement of components such as propulsion motor and powerelectronic means is facilitated, which in turn facilitates compactbuilding-in in the vehicle and thus space saving such that more spacefor e.g. crew and/or payload is obtained. Further efficient drive of thevehicle is facilitated by utilizing electric motor in combination withthe combustion engine according to above.

According to an embodiment of the articulated tracked vehicle saidpropulsion unit comprises a transmission configuration arranged totransfer power for propulsion of the vehicle. Hereby more efficientdrive of the vehicle is facilitated.

According to an embodiment of the articulated tracked vehicle thetransmission configuration comprises at least one planetary gearing. Byusing planetary gearing the transmission configuration may beconstructed more compact which results in saving of space.

According to an embodiment the articulated tracked vehicle comprises anelectric motor per propulsion unit. This results in a more efficientdrive and a compact construction.

According to an embodiment the articulated tracked vehicle comprises twotracks per vehicle unit. This results in stable drive of the trackedvehicle.

According to an embodiment the tracked vehicle comprises an electricmotor per tracked drive wheel and drive shaft. Hereby the driveline maybe formed very compact which results in good space for housing of crewand/or payload. Due to the fact that one electric motor is arranged pertracked drive wheel individual control of the respective track isfacilitated. Hereby pivot turn of the articulated vehicle may beprovided, at least with the front vehicle unit separated. Furthersteering of the vehicle by means of steering of the respective track isfacilitated, which results in the advantage that in case the steering ofthe vehicle control coupling/control member would fail, redundancy inthe form of control by means of the respective track exists.

According to an embodiment the articulated tracked vehicle comprises anelectric motor per vehicle unit. Hereby the driveline may be compactlyformed which results in good saving of space for crew and/or payload.

According to an embodiment the articulated tracked vehicle comprises anelectric motor per pair of first and second, and third and fourth driveshaft respectively. This results in compact design and consequentlysaving of space.

According to an embodiment of the articulated tracked vehicle eachelectric motor is arranged to drive a shaft running in the longitudinaldirection of the vehicle. Hereby shaft and differential of aconventional driveline may at least to a certain extent be utilizedwhich results in easy and cost efficient upgrading of a conventionalarticulated tracked vehicle.

According to an embodiment the articulated tracked vehicle comprisesonly one electric motor which is arranged in the first vehicle unit.Hereby a compact and consequently space saving solution is facilitated.

According to an embodiment of the articulated tracked vehicle theelectric motor is arranged to drive a shaft running in the longitudinaldirection of the vehicle. Hereby shaft and differential of aconventional driveline may at least to a certain extent be utilizedwhich results in easy and cost efficient upgrading of a conventionalarticulated tracked vehicle.

According to an embodiment the articulated tracked vehicle comprisesonly one electric motor which is arranged in the second vehicle unit.Hereby a compact and consequently space saving solution is facilitated.

According to an embodiment of the articulated tracked vehicle thecombustion engine is arranged to drive a shaft running in thelongitudinal direction of the vehicle. Hereby shaft and differential ofa conventional driveline may at least to a certain extent be utilizedwhich results in easy and cost efficient upgrading of a conventionalarticulated tracked vehicle.

Articulated tracked vehicle according to any preceding claims,comprising an energy storage unit arranged to supply energy to saidpower electronic means. Hereby drive of the vehicle with the combustionengine shut off is facilitated wherein more silent drive is facilitated.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention will be had upon thereference to the following detailed description when read in conjunctionwith the accompanying drawings, wherein like reference characters referto like parts throughout the several views, and in which:

FIG. 1a schematically illustrates an articulated tracked vehicle with adriveline according to a first embodiment of the present invention;

FIG. 1b schematically illustrates a cross section of a propulsion unitof the driveline according to FIG. 1 a;

FIG. 2a schematically illustrates an articulated tracked vehicle with adriveline according to a second embodiment of the present invention;

FIG. 2b schematically illustrates a cross section of a propulsion unitof the driveline according to FIG. 2 a;

FIG. 3 schematically illustrates an articulated tracked vehicle with adriveline according to a third embodiment of the present invention;

FIG. 4 schematically illustrates an articulated tracked vehicle with adriveline according to a fourth embodiment of the present invention;

FIG. 5 schematically illustrates an articulated tracked vehicle with adriveline according to a fifth embodiment of the present invention; and

FIG. 6 schematically illustrates a side view of an articulated trackedvehicle with a driveline according to an embodiment of the presentinvention.

DETAILED DESCRIPTION

FIGS. 1a, 2a , 3-5 schematically illustrate an articulated trackedvehicle I; II; III; IV; V with a driveline according to differentembodiments of the present invention. The tracked vehicle I; II; III;IV; V according to the embodiments below comprise a first front vehicleunit 1 and a second rear vehicle unit 2 controllably interconnected bymeans of control coupling/control member 3.

The front vehicle unit 1 has a first track 4 a arranged to be driven bymeans of a first drive wheel 5 a connected to a first drive shaft 6 aand a second track 4 b arranged to be driven by means of a second drivewheel 5 b connected to a second drive shaft 6 b. The rear vehicle unit 2has a third track 5 c arranged to be driven by means of a third drivewheel 5 c connected to a third drive shaft 6 c and a fourth track 5 darranged to be driven by means of a fourth drive wheel 5 d connected toa fourth drive shaft 6 d.

The driveline comprises a combustion engine 10, according to anembodiment a diesel engine, arranged to drive a generator 132 forelectric generation, wherein the generator is arranged to transfer powervia power electronic means 20 to at least one propulsion motor.

The articulated vehicle I; II; III; IV; V according to the presentinvention comprises according to an embodiment an electronic controlunit 30 arranged to control the combustion engine 10 and powerelectronic means 20 for controlling propulsion motor.

The articulated vehicle I; II; III; IV; V according to an embodimentfurther comprises an actuator 40 for power request, the actuatoraccording to an embodiment comprising a gas trigger, such as anaccelerator pedal. Power request is generated on the basis of an actionperformed by the driver corresponding to a desire of the driver to givepower to the vehicle for propulsion of the same. The actuator comprisesaccording to a variant means for actuating drive of the respectivepropulsion member/electric motor, which according to a variant isprovided by a control panel or the corresponding, from which a requestfor desired control is requested, wherein information is treated andtransferred to the power electronic means 20, wherein information/poweris forwarded to the propulsion motor/electric motor.

The electronic control unit is signal connected to the actuator 40 forpower request via a link. A driver of the vehicle may request a power tothe combustion engine 10 by means of the actuator. A driver of thevehicle may request drive of propulsion motor by means of the actuator40. The electronic control unit 30 is arranged to receive datarepresenting requested power from the actuator 40. The electroniccontrol unit 30 is arranged to communicate via a link with the powerelectronic means 20 wherein the requested power is compared to requiredpower. If required power is not sufficient the electronic control unit30 is arranged to communicate with the combustion engine 10 to increasethe rotational speed for increased power, wherein increased power issent to the generator 12 which transfers the power to the powerelectronics 20 for forwarding to electric motor for drive of thevehicle.

According to a variant of the present invention such as described in theembodiments below the driveline comprises an energy storage unit 50arranged to store energy. The energy storage unit is connected to saidpower electronic means 20 via a link for supplying the power electronicmeans with power. The energy storage unit 50 is arranged to store energye.g. when the vehicle is braking, wherein the electric motor acts asgenerator such that the electric motor then generates a current which isarranged to be stored in the energy storage unit 50.

By the energy storage unit 50 drive of the vehicle with the combustionengine shut off is facilitated wherein more silent drive is facilitated.

The energy storage unit 50 according to the variant of the presentinvention as described in the embodiments below may be any suitableenergy storage unit 50. According to a variant the energy storage unitis constituted by a battery or battery pack. According to an alternativevariant the energy storage unit is constituted by a capacitor such as asuper capacitor.

Herein the term “link” is referred to as a communication link which maybe a physical line, such as an opto-electronic communication line, or anon-physical line, such as a wireless connection, e.g. a radio link ormicrowave link.

Herein the term “propulsion motor” is referred to as an electric motorfor propulsion of the articulated tracked vehicle according to thepresent invention.

Herein the term “power electronic means” and “power electronic unit” arereferred to as means/unit which among others is configured to convertalternating voltage/alternating current to continuous voltage/continuouscurrent and vice versa, configured to transform up or down voltage, andfacilitates connection to energy storage unit such as battery, capacitoror the corresponding. Further the means is configured to controlrotational speed/torque of electric motors, i.e. power. The powerelectronic means/power electronic unit is e.g. arranged to convertalternating current from a generator to continuous current for supply ofe.g. lamps, radio and the like; converting high voltage, e.g. 500 or 600V, to lower voltage, e.g. 12, 24 or 48 V; converting low voltage, e.g.12, 24 or 48 V, from energy storage unit to high voltage, e.g. 500 or600 V; and transferring high voltage to electric motors.

FIG. 1a schematically illustrates an articulated tracked vehicle I witha driveline according to a first embodiment of the present invention.

The driveline comprises a combustion engine 10, e.g. a diesel engine,and a generator, wherein the combustion engine 10 is arranged to drivethe generator 12.

The driveline further comprises a first electric propulsion unit 100 acomprising a first propulsion motor 101 and a first transmissionconfiguration 102 connected to the first drive shaft 6 a and arranged todrive the first drive wheel 5 a. The driveline further comprises asecond electric propulsion unit 100 b comprising a second propulsionmotor 103 and a transmission configuration 104 connected to the seconddrive shaft 6 b and arranged to drive the second drive wheel 5 b. Thedriveline further comprises a third propulsion unit 100 c comprising athird propulsion motor 105 and a third transmission configuration 106connected to the third drive shaft 6 c and arranged to dive the thirddrive wheel 6 c. The driveline further comprises a fourth electricpropulsion unit 100 d comprising a fourth propulsion motor 107 and afourth transmission configuration 108 connected to the fourth driveshaft 6 d and arranged to drive the fourth drive wheel 5 d.

The driveline further comprises power electronic means 20 connected tothe generator 12 and arranged to receive power from the generator 12,wherein said power electronic means 20 are arranged to transfer power tothe respective propulsion motor 101, 103, 105, 107.

The power electronic means 20 comprises a first power electronic unit21, a second power electronic unit 22 and a third power electronic unit23, the first, second and third power electronic units being connectedto each other. The first power electronic unit 21 is arranged totransfer power to the first propulsion motor 101 via a first link 111.The first power electronic unit 21 is further arranged to transfer powerto the second propulsion motor 103 via a second link 112. The secondpower electronic unit 22 is arranged to transfer power to the thirdpropulsion motor 105 via a third link 113. The second power electronicunit 22 is further arranged to transfer power to the fourth propulsionmotor 107 via a fourth link 114.

According to an alternative variant the first, second and third powerelectronic units 21, 22, 23 could be constituted by a single powerelectronic unit.

The respective propulsion motor is here constituted by an electric motorfor propulsion of the articulated tracked vehicle I. In the respectiveelectric propulsion unit 100 a, 100 b, 100 c, 100 d the respectivepropulsion motor 101, 103, 105, 107 is connected to the respectivetransmission configuration 102, 104, 106, 108. An embodiment of anelectric propulsion unit 100 a for the first embodiment is illustratedin FIG. 1b , described below.

The articulated tracked vehicle I further comprises the electroniccontrol unit 30. The electronic control unit 30 is signal connected tothe combustion engine 10 for controlling the combustion engine 10 via alink. The electronic control unit 30 is further signal connected to saidpower electronic means 20 wherein the electronic control unit 30 isarranged to control the first power electronic unit 21 via a link, thesecond power electronic unit 22 via a link, and the third powerelectronic unit 23 via a link. The electronic control unit 30 isarranged to communicate between the combustion engine 10 and powerelectronic means 20. The electronic control unit 30 is signal connectedto the actuator 40 for power request via a link.

According to a variant the electronic control unit 30 and the powerelectronic means 20 could be constituted by a common unit for controland communication between combustion engine 10 and propulsion motors101, 103, 105, 107, wherein said common unit is connected to thecombustion engine 10, generator 12, propulsion motors 101, 103, 105, 107and actuator 40.

Due to the fact that the combustion engine 10 is arranged to drive agenerator 12 which then transfers power to said power electronicsgenerating power to the propulsion motor no mechanical powertransmission is required from the combustion engine 10 to the drivewheel 5 a, 5 b, 5 c, 5 d. Hereby relatively free placement of componentssuch as electric propulsion unit and power electronic means isfacilitated.

According to a variant of the first embodiment the driveline comprisesan energy storage unit 50 arranged to store energy. The energy storageunit 50 is connected to the third power electronic unit 23 via a link115 for supplying the power electronic means with power. Hereby drive ofthe vehicle I with the combustion engine 10 shut off is facilitatedwherein more silent drive is facilitated.

By using an electric propulsion motor 101, 103, 105, 107 according tothe first embodiment, i.e. an electric motor, per track 4 a, 4 b, 4 c, 4d, the driveline may be designed very compact which results in goodspace for housing of crew and/or payload. By having a propulsion motor,i.e. an electric motor, arranged per track individual control of therespective track is facilitated. Hereby a pivot turn of the articulatedtracked vehicle would be obtainable. Further the vehicle I would besteerable by means of control of each track, which results in theadvantage that in case of failure of the steering of the controlcoupling/control member 3, redundancy in the form a steering by means ofthe respective track 4 a, 4 b, 4 c, 4 d exists.

According to a variant each propulsion motor may be individuallycontrolled via the actuator 40, wherein the control commands from theactuator 40 are processed in the electronic control unit 30 fortransmission of power to the respective power electronic unit 21, 22, 23of the power electronic means 20. Hereby is facilitated to obtain anopen as well as a locked differential for the entire articulated trackedvehicle I.

FIG. 1b schematically illustrates a cross section of an electricpropulsion unit 100 a as the first electric propulsion unit 100 a of thedriveline according to FIG. 1 a.

The electric propulsion unit 100 a comprises a propulsion motor 101,i.e. an electric motor for propulsion of the articulated tracked vehicleI. The propulsion motor 101 has a rotor 101 a arranged to rotate and astator 101 b being fixedly secured, e.g. in a housing of a gearbox.

The electric propulsion unit 100 a further comprises a transmissionconfiguration 102 connected to the propulsion motor 101 and arranged totransfer the rotational speed from the rotor 101 a of the propulsionmotor to the drive shaft for driving of the drive wheel.

The transmission configuration 102 comprises a planetary gearing 130connected to the rotor 101 a. The planetary gearing 130 comprises a sunwheel 131, planet wheels 132 and a ring wheel 133. The sun wheel 131 isconnected to the rotor 101 a via a shaft such that the sun wheel 131 isarranged to be rotated by means of the rotor 101 a. The transmissionconfiguration 102 has a high gear position H in which the entireplanetary gearing 130 with the ring wheel 133 rotates with an inputshaft of the planetary gearing running from the rotor 101 a to the sunwheel 131 of the planetary gearing 130. The planetary gearing 130further has a low gear position L in which the ring wheel 133 is lockedand the planet wheels 132 rotate with the sun wheel 131 which provides agear reduction on the drive shaft 6 a such that it rotates with a lowerrotational speed.

The transmission configuration 102 also comprises a reduction gear 140connected to the planetary gearing 130 and the drive shaft 6 a. Thereduction gear 140 is arranged to reduce the rotation coming from theplanetary gearing 130 such that a lower rotational speed but highertorque is provided. The reduction gear 140 comprises a sun wheel, planetwheels 142 and a ring wheel 143. The reduction gear 140 is connected tothe drive shaft 6 a via its planet wheel 142 for providing a gearreduction. In the high gear position H of the transmission configurationthe sun wheel 141 of the reduction gear 140 rotates with a higherrotational speed compared to the low gear position L. The ring wheel 143is always locked to the housing of the gear box independent of high gearposition H or low gear position L.

The reduction gear is a type of planetary gearing. The respectivetransmission configuration 102, 104, 106, 108 of the first embodiment isbuilt up of planetary gearing/reduction gear 130/140. Thereby a compactconstruction is obtained which results in more space for crew and/orpayload.

The articulated vehicle I comprises a brake device 150 arranged to brakethe drive shaft 6 a. Any suitable brake device could be used, such aswheel brake drum, electric brake, disc brake or wet brake.

Above a transmission configuration 102 suitable for the first embodimentof the present invention has been described. Any suitable configurationof an electric propulsion unit 100 a/transmission configuration 102could be used though.

FIG. 2a schematically illustrates an articulated tracked vehicle II witha driveline according to a second embodiment of the present invention.

The driveline comprises a combustion engine 10, e.g. a diesel engine,and a generator 12 for electric generation, wherein the combustionengine 10 is arranged to drive the generator 12.

The driveline further comprises a first electric propulsion unit 200 acomprising a first propulsion motor connected to the first and seconddrive shaft 6 a, 6 b and arranged to drive the first and second drivewheel 5 a, 5 b. The driveline further comprises a second electricpropulsion unit 200 b comprising a second propulsion motor connected tothe third and fourth drive shaft 6 c, 6 d and arranged to drive thethird and fourth drive wheel 5 c, 5 d. Each electric propulsion unitfurther comprises a transmission configuration.

The driveline further comprises power electronic means 20 connected tothe generator 12 via a link and arranged to receive power from thegenerator 12, wherein said power electronic means 20 is arranged totransfer power to the respective propulsion motor 200 a, 200 b. Thepower electronic means 20 comprises a first power electronic unit 21, asecond power electronic unit 22 and a third power electronic unit 23,the first, second and third power electronic unit being connected toeach other. The first power electronic unit 21 is arranged to transferpower to the first propulsion motor 200 a via a first link 211. Thesecond power electronic unit 22 is arranged to transfer power to thesecond propulsion motor 200 b via a second link 212.

Each propulsion motor of the respective electric propulsion unit 200 a,200 b are here constituted by an electric motor for propulsion of thearticulated tracked vehicle II. An embodiment of electric propulsionunit 200 a for the second embodiment is illustrated in FIG. 2b ,described below.

The articulated vehicle II further comprises the electronic control unit30. The electronic control unit 30 is signal connected to the combustionengine 10 for controlling the combustion engine 10 via a link. Theelectronic control unit 30 is further signal connected to said powerelectronic means 20 wherein the electronic control unit 30 is arrangedto control the first power electronic unit via a link, the second powerelectronic unit via a link, and the third power electronic unit via alink. The electronic control unit 30 is arranged to communicate betweencombustion engine 10 and power electronic means 20. The electroniccontrol unit 30 is signal connected to the actuator 40 for power requestvia a link.

According to a variant the electronic control unit 30 and the powerelectronic means 20 could be constituted by a common unit for controland communication between combustion engine 10 and propulsion motors,wherein said common unit is connected to the combustion engine 10,generator 12, propulsion motors and actuator 40.

According to a variant of the second embodiment the driveline comprisesan energy storage unit 50 arranged to store energy. The energy storageunit 50 is connected to the third power electronic unit 23 via a link215 for providing the power electronic means with power. Herby drive ofthe vehicle with the combustion engine 10 shut off is facilitatedwherein more silent drive is facilitated.

By using an electric propulsion motor, i.e. electric motor forpropulsion of the articulated tracked vehicle II, in accordance with thesecond embodiment of the respective propulsion unit 200 a, 200 b, thedriveline may be designed very compact which results in good saving ofspace for crew and/or payload. Further the device with electricpropulsion unit 200 a, 200 b comprising propulsion motor andtransmission configuration facilitates regulation of the outputrotational speed of the respective drive shaft and thus controlling therespective vehicle.

FIG. 2b schematically illustrates a cross section of an electricpropulsion unit 200 a of the driveline according to FIG. 2 a.

The electric propulsion unit 200 a comprises a propulsion motor 201,i.e. an electric motor for propulsion of the articulated tracked vehicleII, an electric motor 201 per pair of first and second, and third andfourth drive shaft 6 a-b, 6 c-d respectively. The propulsion motor 201is arranged per pair of first and second drive wheel 5 a, 5 b to drivefirst and second drive wheels 5 a, 5 b (see FIG. 2a ) by being arrangedper pair of first and second drive shafts 6 a, 6 b to rotate oppositedrive shafts. The propulsion motor 201 has a rotor 201 a arranged torotate and a stator 201 b being fixedly secured, e.g. in a housing of agearbox for the transmission configuration 202.

The electric propulsion unit 200 a further comprises a transmissionconfiguration 202 connected to the propulsion motor 201 and arranged totransfer the rotational speed from the rotor 201 a of the propulsionmotor 201 to the opposite drive shafts 6 a, 6 b for driving of the drivewheels connected to the respective drive shaft.

The transmission configuration 202 comprises a planetary gearing 230connected to the rotor 201 a. The planetary gearing comprises a sonwheel 231, planet wheel 232 and a ring wheel 233. The sun wheel 231 isconnected to the rotor 201 a via a shaft such that the sun wheel 231 isarranged to be rotated by means of the rotor 201 a. The planetarygearing 230 has a high gear position H in which the entire planetarygearing 230 with the ring wheel 233 rotates with an input shaft of theplanetary gearing 230. The planetary gearing 230 further has a low gearposition L in which the ring wheel is locked and the planet wheels 232rotate with the sun wheel 231 which provides a gear reduction on theoutput shaft such that it rotates with a lower rotational speed.

The transmission configuration 202 also comprises a first reduction gear240 a connected to the first drive shaft 6 a and a second reduction gear240 b connected to the second drive shaft 6 b. The transmissionconfiguration 202 also comprises a differential 260 arranged to adaptthe speed between the drive wheels. The first reduction gear 240 a andthe second reduction gear 240 b are connected to each other via thedifferential 260.

The first reduction gear 240 a is further connected to the planetarygearing 230. The first reduction gear 240 a is arranged to reduce therotation coming from the planetary gearing 230 such that a lowerrotational speed but higher torque is obtained to the drive shaft 6 a.

The first reduction gear 240 a comprises a sun wheel 241, planet wheels242 and a ring wheel 243. The first reduction gear 240 a is connected tothe first drive shaft 6 a via its planet wheels 242 for providing gearreduction. The second reduction gear 240 b comprises a sun wheel 244,planet wheels 245 and a ring wheel 246. The second reduction gear 240 bis connected to the second drive shaft 6 b via its planet wheel 245 forprovision of gear reduction.

The first and second reduction gear 240 a, 240 b are further connectedto each other via a shaft 247 connected to the sun wheel 241, 244 of therespective reduction gear 240 a, 240 b. The first and second reductiongear 240 a, 240 b are connected via the differential 260 between therespective ring wheel.

In the high range position H of the transmission configuration 202 thesun wheel 241, 244 of the first and second reduction gear 240 a, 240 brotates with a higher rotational speed. The ring wheel 243, 246 of thefirst and second reduction gear 240 a, 240 b is always locked. Theplanet wheels 242, 245 of the first and second reduction gear 240 a, 240b rotate with its respective sun wheel 241, 244 which results in a gearreduction on the respective drive shaft 6 a, 6 b such that it rotateswith a lower rotational speed. The ring wheel 233 is in the low gearposition L arranged to be locked to the housing of the gear box and in ahigh gear position H arranged to be locked to the input shaft of the sunwheel running from the rotor 201 a.

The electric propulsion unit 200 a according to a variant furthercomprises an electric motor 270 arranged in connection to thedifferential 260 to regulate output rotational speed to in such a wayfacilitate control of the respective drive wheel and thus steering ofthe vehicle unit in which the electric propulsion unit 200 a isarranged. This results in the advantage that in case the steering of thecontrol coupling/control member would fail, redundancy in the form asteering by means of each track is possible.

Each reduction gear 240 a, 240 b is a type of planetary gearing. Due tothe fact that each transmission configuration of the first embodiment isbuilt up of a planetary gearing/reduction gear a compact construction isobtained which results in more space for crew and/or payload.

The articulated tracked vehicle comprises a brake device 250 a, 250 bfor the respective drive wheel arranged to brake the respective driveshaft 6 a, 6 b. Any suitable brake device could be used, such as brakedrum, electric brake, disc brake or wet brake.

Above a transmission configuration 202 suitable for the secondembodiment of the present invention has been described. Any suitableconfiguration of electric propulsion unit/transmission configurationcould be used though.

FIG. 3 schematically illustrates an articulated tracked vehicle III witha driveline according to a third embodiment of the present invention.

The driveline comprises a combustion engine 10, e.g. a diesel engine,and a generator 12, wherein the combustion engine 10 is arranged todrive the generator 12.

The driveline further comprises an electric propulsion unit 300 arrangedin the front vehicle unit comprising a propulsion motor 301 arranged todrive a shaft 310 running in the longitudinal direction of the vehicleIV. The propulsion motor 301 is via the shaft 310 connected to the firstand second drive shaft 6 a, 6 b via a first shaft gear/differential 303and arranged to drive the first and second drive wheel 5 a, 5 b, thefirst shaft gear/differential 303 being arranged in the first vehicleunit 1 in connection to the first and second drive shaft 6 a, 6 b.

The propulsion motor 301 is further connected to the third and fourthdrive shaft 6 c, 6 d via a second shaft gear/differential 304 andarranged to drive the third and fourth drive wheel 5 c, 5 d, the secondshaft gear/differential 304 being arranged in the second vehicle unit 2in connection to the third and fourth drive shaft 6 c, 6 d.

The electrical propulsion unit 300 further comprises a transmissionconfiguration 302 connected to the propulsion motor 301. Thetransmission configuration 302 is according to this variant arrangedbehind the propulsion motor 301. The propulsion motor 301 and thetransmission configuration 302 are arranged in connection to the shaft310 running in the longitudinal direction of the vehicle. The shaft 310is coupled in its front end to said first shaft gear/differential 303.The main shaft 310 is coupled in its rear end to said second shaftgear/differential 304.

The driveline further comprises power electronic means 20 connected tothe generator 12 and arranged to receive power from the generator 12,wherein said power electronic means 20 are arranged to transfer power tothe propulsion motor 301. The power electronic means 20 comprises afirst power electronic unit 21 and a second power electronic unit 22,the first and second power electronic unit 21, 22 being connected toeach other. The first power electronic unit 21 is arranged to transferpower to the first propulsion motor 301 via a first link 311.

The propulsion motor 301 is here constituted by an electric motor forpropulsion of the articulated tracked vehicle III.

The articulated tracked vehicle further comprises the electronic controlunit 30. The electronic control unit 30 is signal connected to thecombustion engine 10 for controlling the combustion engine 10 via alink. The electronic control unit 30 is further signal connected to saidpower electronic means 20 wherein the electronic control unit 30 isarranged to control the first power electronic unit 21 via a link andthe second power electronic unit 22 via a link. The electronic controlunit 30 is arranged to communicate between combustion engine 10 andpower electronic means 20. The electronic control unit 30 is signalconnected to the actuator 40 for power request via a link 315.

According to a variant the electronic control unit 30 and the powerelectronic means 20 could be constituted by a common unit for controland communication between combustion engine 10 and propulsion motors,wherein said common unit is connected to combustion engine 10, generator12, propulsion motor 301 and actuator 40.

According to a variant of the second embodiment the driveline comprisesan energy storage unit 50 arranged to store energy. The energy storageunit 50 is connected to the second power electronic unit via a link 315for providing the power electronic means 20 with power. Hereby drive ofthe articulated tracked vehicle III with the combustion engine 10 shutoff is facilitated wherein more silent drive is facilitated.

An advantage with a driveline according to the third embodiment is thatpropulsion motor 301, i.e. electric motor for propulsion of thearticulated tracked vehicle III, may be arranged on an existingmechanical driveline and consequently upgrading of an articulatedtracked vehicle with conventional mechanical driveline may be providedrelatively easy and cost efficient.

FIG. 4 schematically illustrates an articulated tracked vehicle IV witha driveline according to a fourth embodiment of the present invention.

The driveline comprises a combustion engine 10, e.g. a diesel engine,and a generator 12, wherein the combustion engine 10 is arranged todrive the generator 12.

The driveline further comprises a first electrical propulsion unit 400 aarranged in the front vehicle unit and comprising a first propulsionmotor 401 arranged to drive a first shaft 410 a running in thelongitudinal direction of the vehicle IV. The first propulsion motor 401is via a the first shaft 410 a connected to the first and second driveshaft 6 a, 6 b via a first shaft gear/differential 405 and arranged todrive the first and second drive wheel 5 a, 5 b, the first shaftgear/differential 405 being arranged in the first vehicle unit 1 inconnection to the first and second drive shaft 6 a, 6 b.

The driveline further comprises a second electric propulsion unit 400 barranged in the rear vehicle unit and comprising a second propulsionmotor 402 arranged to drive a second shaft running in the longitudinaldirection of the vehicle IV. The first propulsion motor 401 is via thesecond shaft 410 b connected to the third and fourth drive shaft 6 c, 6d via a second shaft gear/differential 406 and arranged to drive thethird and fourth drive wheel 5 c, 5 d, the second shaftgear/differential being arranged in the second vehicle unit 2 inconnection to the third and fourth drive shaft 6 c, 6 d.

The first electric propulsion unit 400 a further comprises a firsttransmission configuration 402 arranged in connection to the firstpropulsion motor 401. The first transmission configuration 402 isaccording to this variant arranged behind the first propulsion motor401. The first propulsion motor 401 and the first transmissionconfiguration 402 are arranged in connection to the longitudinal firstshaft 410 a. The first shaft 410 a is coupled in its front end to saidfirst shaft gear/differential 405 and in its rear end to said firsttransmission configuration 402 and first propulsion motor. The firstpropulsion motor is arranged to drive said first main drive shaft.

The second electric propulsion unit 400 b further comprises a secondtransmission configuration 404 arranged in connection to the secondpropulsion motor 403. The second transmission configuration 404 isaccording to this variant arranged behind the second propulsion motor403. The second propulsion motor 403 and the second transmissionconfiguration 404 are arranged in connection to the longitudinal secondshaft 410 b. The second shaft 410 b is coupled in its front end to saidsecond shaft gear/differential 406 and in its rear end to said secondtransmission configuration 404 and second propulsion motor 403.

The driveline further comprises power electronic means 20 connected tothe generator 12 and arranged to receive power from the generator 12,wherein said power electronic means 20 are arranged to transfer power tothe respective propulsion motor 402, 403. The power electronic meanscomprises a first power electronic unit 21, a second power electronicunit 22 and a third power electronic unit 23, the first, second andthird power electronic units being connected to each other. The firstpower electronic unit 21 is arranged to transfer power to the firstpropulsion motor 401 via a first link 411. The second power electronicunit 22 is arranged to transfer power to the second propulsion motor 404via a second link 411.

Each propulsion motor 401, 403 is here constituted by an electric motorfor propulsion of the articulated tracked vehicle IV.

The articulated tracked vehicle further comprises the electronic controlunit 30. The electronic control unit 30 is signal connected to thecombustion engine 10 via link for controlling the combustion engine 10.The electronic control unit 30 is further signal connected to said powerelectronic means 20 wherein the electronic control unit 30 is arrangedto control the first power electronic unit 21 via a link, the secondpower electronic unit 22 via a link, and the third power electronic unit23 via link. The electronic control unit 30 is arranged to communicatebetween combustion engine 10 and power electronic means 20. Theelectronic control unit 30 is signal connected to the actuator 40 forpower request via a link.

According to a variant the electronic control unit 30 and the powerelectronic means 20 could be constituted by a common unit for controland communication between combustion engine 10 and propulsion motors401, 403, wherein said common unit is connected to combustion engine 10,generator 12, propulsion motors 401, 403 and actuator 40.

According to a variant of the second embodiment the driveline comprisesan energy storage unit 50 arranged to store energy. The energy storageunit 50 is connected to the third power electronic unit 23 via a link415 for providing the power electronic means with power. Thereby driveof the articulated tracked vehicle IV with the combustion engine 10 shutoff is facilitated wherein more silent drive is facilitated.

By arranging propulsion motor 401, 403, i.e. electric motor, e.g.steering motor, in accordance with the fourth embodiment directly on thetransmission configuration 402, 404 in the form of shaft gears arelatively simple construction which is reliable is obtained, sinceexisting shaft gear is already tried out, and no new differential of theshaft gear needs to be constructed. Further problem with design of a newbrake system is eliminated. By arranging a propulsion motor 401, 403 pervehicle unit in accordance with the fourth embodiment redundancy in caseany of the propulsion motors would fail is obtained. The constructionwith an electric propulsion unit 400 a, 400 b, i.e. propulsion motorconnected to transmission configuration, in each vehicle unitfacilitates a relatively compact solution such that more space for crewand/or payload is set free.

FIG. 5 schematically illustrates an articulated tracked vehicle V with adriveline according to a fifth embodiment of the present invention.

The driveline comprises a combustion engine 10, e.g. a diesel engine,and a generator 12, wherein the combustion engine 10 is arranged todrive the generator 12. The generator 12 is according to this embodimentarranged in front of the combustion engine 10.

The combustion engine 10 is connected to the first and second driveshaft 6 a, 6 b via a shaft gear/differential 505, wherein the combustionengine 10 is arranged to drive the first and second drive wheel 5 a, 5 bvia said shaft gear/differential.

A first transmission configuration is arranged in connection to thecombustion engine 10. The first transmission configuration 11 isaccording to this variant arranged in front of the generator 12. Thecombustion engine 10 and first transmission configuration 11 constitutea mechanical propulsion unit. The combustion engine 10 and firsttransmission configuration 11 are arranged to drive a shaft 13 runningin the longitudinal direction of the vehicle. The shaft 13 is coupled inits front end to said first drive shaft/differential 505 and in the rearend with the transmission configuration 11/combustion engine 10.

The driveline further comprises an electric propulsion unit 500 arrangedin the rear vehicle unit comprising a propulsion unit 501 and secondtransmission configuration 502 connected to the third and fourth driveshaft 6 c, 6 d and arranged to drive the third and fourth drive wheel 5c, 5 d.

The driveline further comprises power electronic means 20 connected tothe generator 12 and arranged to receive power from the generator 12,wherein said power electronic means 20 are arranged to transfer power tothe propulsion motor 501. The power electronic means 20 comprises afirst power electronic unit 21 and a second power electronic unit 22,the first and second power electronic unit being connected to eachother. The first power electronic unit 21 is arranged to transfer powerto the propulsion motor 501 via link 511.

The propulsion motor 501 of the electric propulsion unit is constitutedby an electric motor for propulsion of the articulated vehicle V.

The articulated vehicle further comprises the electronic control unit30. The electronic control unit 30 is signal connected to the combustionengine 10 for controlling the combustion engine 10 via a link. Theelectronic control unit 30 is further signal connected to said powerelectronic means 20 wherein the electronic control unit 30 is arrangedto control the first power electronic unit 21 via a link and the secondpower electronic unit 22 via a link. The electronic control unit 30 isarranged to communicate between combustion engine 10 and powerelectronic means 20. The electronic control unit 30 is signal connectedto the actuator 40 for power request via a link.

According to a variant the electronic control unit 30 and the powerelectronic means 20 could be constituted by a common unit for controland communication between combustion engine 10 and propulsion motor 501,wherein said common unit is connected to combustion engine 10, generator12, propulsion motor 501 and actuator 40.

According to a variant of the second embodiment the driveline comprisesan energy storage unit 50 arranged to store energy. The energy storageunit 50 is connected to the second power electronic unit 22 via a link515 for providing the power electronic means 22 with power. Hereby driveof the vehicle with the combustion engine 10 shut off is facilitatedwherein more silent drive is facilitated.

By means of the device according to the fifth embodiment mechanicaldrive by means of the mechanical electric propulsion unit, electricdrive by means of the electric propulsion unit 500 or a combination ofmechanical and electric drive by means of the mechanical and electricalpropulsion unit is facilitated.

According to a variant the electric propulsion unit may be utilized atlower speeds and be replaced by the mechanical propulsion unit at higherspeeds. The device according to the fifth embodiment facilitatesconstruction the electrical propulsion unit 500 such that this is onlyused for half the maximal speed wherein lower rotational speed isobtained. Hereby no distribution box and also no cardan shaft undercombustion engine, to a certain extent free placement of componentswhich facilitates a more compact construction than conventionaldriveline and is consequently space saving.

FIG. 6 schematically illustrates a side view of an articulated trackedvehicle with a driveline according to an embodiment of the presentinvention. Hereby placement of driveline in accordance with the first orsecond embodiment is illustrated.

The articulated tracked vehicle I; II comprises the front vehicle unit 1and the rear vehicle unit 2 controllably interconnected by means of thecontrol coupling/control member 3. In the front vehicle unit thecombustion engine 10 is arranged in the front portion, the generator 12is arranged behind the combustion engine 10 and the first, second andthird power electronic units 21, 22, 23 and electronic control unit 30behind the generator 12. The electric propulsion units 100 a-d; 200 a-bare arranged in connection to the drive wheels of the respective vehicleunit 1, 2.

Above different embodiments of an articulated tracked vehicle comprisinga first vehicle unit 1 and a second vehicle unit 2 controllablyconnected by means of a control member 3, the combustion engine 10 beingarranged to drive a generator 12 for electric generation, wherein thegenerator 12 is arranged to transfer power to at least one electricmotor of at least one electric propulsion unit via power electronicmeans 20. Hereby no mechanical power transfer from the combustion engineto drive wheels of the vehicle is required, wherein relatively freeplacement of electric motor/propulsion unit is facilitated. Consequentlyelectric motor/propulsion unit may be arranged in connection to therespective vehicle unit and consequently, depending on embodiment anddesign of the vehicle unit be placed in the vehicle body of first and/orsecond vehicle unit 1, 2, outside of the vehicle body of the firstand/or second vehicle unit 1, 2 and/or between first and second vehicleunit 1, 2.

The foregoing description of the preferred embodiments of the presentinvention has been provided for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Obviously, many modificationsand variations will be apparent to practitioners skilled in the art. Theembodiments were chosen and described in order to best explain theprinciples of the invention and its practical applications, therebyenabling others skilled in the art to understand the invention forvarious embodiments and with the various modifications as are suited tothe particular use contemplated.

The invention claimed is:
 1. An articulated tracked vehicle comprising afirst vehicle unit and a second vehicle unit controllably connected bymeans of a control member, wherein each vehicle unit comprises twotracks driven by drive wheels, wherein the first vehicle unit comprisesa mechanical propulsion unit with a combustion engine for driving thedrive wheels of the first vehicle unit and the second vehicle unitconsists of one electric propulsion unit for driving the drive wheels ofthe second vehicle unit, wherein the combustion engine is arranged todrive a generator for electric power generation, wherein the generatoris arranged to transfer electric power via power electronics to theelectric propulsion unit of the second vehicle unit, wherein propulsionpower transfer between said vehicle units consists of an electricalconnection.
 2. An articulated tracked vehicle according to claim 1,wherein the mechanical propulsion unit further comprises a firsttransmission configuration arranged in connection to the combustionengine.
 3. An articulated tracked vehicle according to claim 2, whereinthe mechanical propulsion unit is arranged to drive a shaft running inthe longitudinal direction of the vehicle.
 4. An articulated trackedvehicle comprising a first vehicle unit and a second vehicle unitcontrollably connected by means of a control member, wherein eachvehicle unit comprises two tracks driven by drive wheels, wherein thefirst vehicle unit comprises a mechanical propulsion unit with acombustion engine for driving the drive wheels of the first vehicle unitand the second vehicle unit consists of one electric propulsion unit fordriving the drive wheels of the second vehicle unit, wherein thecombustion engine is arranged to drive a generator for electric powergeneration, wherein the generator is arranged to transfer electric powervia power electronics to the electric propulsion unit of the secondvehicle unit, wherein power transfer between said vehicle units isarranged to be effected only electrically, wherein the mechanicalpropulsion unit further corn irises a first transmission configurationarranged in connection to the combustion engine, wherein the mechanicalpropulsion unit is arranged to drive a shaft running in the longitudinaldirection of the vehicle, and wherein the shaft is coupled at its frontend with a first shaft gear/differential and in its rear end with themechanical propulsion unit.
 5. An articulated tracked vehicle accordingto claim 4, wherein the combustion engine is arranged to drive a firstand second drive shaft, and thus a first and second drive wheel, via thefirst shaft gear/differential.
 6. An articulated tracked vehicleaccording to claim 5, wherein said electric propulsion unit consists ofone electric motor and a second transmission configuration connected toa third and fourth drive shaft and arranged to drive a third and fourthdrive wheel.
 7. An articulated tracked vehicle according to claim 2,wherein the first transmission configuration comprises at least oneplanetary gearing.
 8. An articulated tracked vehicle according to claim1, comprising an energy storage unit arranged to supply energy to saidpower electronic means.
 9. An articulated tracked vehicle according toclaim 1, wherein the mechanical propulsion unit is arranged to drive ashaft running in the longitudinal direction of the vehicle.
 10. Anarticulated tracked vehicle according to any of claim 1, wherein saidelectric propulsion unit consists of one electric motor and a secondtransmission configuration connected to a third and fourth drive shaftand arranged to drive a third and fourth drive wheel.